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Discussion Starter · #1 ·
What is the preferred way to set up the AC in an E39 for a comfy setting?

Yes. I read the manual, well, the part on the air conditioning anyway. But I was just wondering if any ac setup hints can be had here.

Here's what I do today (for 55 degree nights & 75 degree days).
... I leave the center vents on the three blue dot setting
... I set the driver side temperature to 64 degrees
... I set the passenger side temperature to 68 degrees
... I set the +/- to about the half way point on the orange LED ramp
... I press the AUTO button to let the computer choose where to blow the air (up, down, both)
... I leave the MAX button untouched unless it gets too warm

Even with all that setup, I still find myself constantly messing with the settings, mostly the driver side temperature and fan speeds. Even during a simple half-hour trip, I find myself having to adjust the settings constantly.

I must be doing something wrong.
I can't be the first person to want setting which keeps the car cool to about 66 degrees no matter what the temperature is outside if the ambient temperature ranges between about 55 and 75 degrees fahrenheit.

How do YOU set up the ac in your E39?
... center vents (1, 2, or 3 blue or red dots)?
... driver side temperature (degrees)?
... passenger side temperature (degrees)?
... fan speed (+/- LED ramp)?
... AUTO / UP / DOWN buttons?
... MAX button?
 

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Ahem said:
How do YOU set up the ac in your E39?
It's not perfect, but I find these settings work for me. I like things on the cool side.

... center vents (1, 2, or 3 blue or red dots)?
Usually 1 blue dot, but it varies depending on how much sun is coming into the car. Winter mornings - prob 2 red until the car warms then back to neutral. As we approach summer it stays on 1 or 2 blue.

... driver side temperature (degrees)?
65

... passenger side temperature (degrees)?
65

... fan speed (+/- LED ramp)?
AUTO

... AUTO / UP / DOWN buttons?
AUTO

... MAX button?
off unless it is really hot in the car

Oh, and I switch the A/C off unless it starts getting really hot. I'll open the sunroof to bring the temp of the car down first.
 

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Ahem said:
What is the preferred way to set up the AC in an E39 for a comfy setting?

Yes. I read the manual, well, the part on the air conditioning anyway. But I was just wondering if any ac setup hints can be had here.

Here's what I do today (for 55 degree nights & 75 degree days).
... I leave the center vents on the three blue dot setting
... I set the driver side temperature to 64 degrees
... I set the passenger side temperature to 68 degrees
... I set the +/- to about the half way point on the orange LED ramp
... I press the AUTO button to let the computer choose where to blow the air (up, down, both)
... I leave the MAX button untouched unless it gets too warm

Even with all that setup, I still find myself constantly messing with the settings, mostly the driver side temperature and fan speeds. Even during a simple half-hour trip, I find myself having to adjust the settings constantly.

I must be doing something wrong.
I can't be the first person to want setting which keeps the car cool to about 66 degrees no matter what the temperature is outside if the ambient temperature ranges between about 55 and 75 degrees fahrenheit.

How do YOU set up the ac in your E39?
... center vents (1, 2, or 3 blue or red dots)?
... driver side temperature (degrees)?
... passenger side temperature (degrees)?
... fan speed (+/- LED ramp)?
... AUTO / UP / DOWN buttons?
... MAX button?
I thought there is something wrong with me when i used to drive a 2001 C320 Merc
with Thermotronic (as they call electronic a/c). It had trouble maintaning stable
interior temperature with changing ambient conditions. It was very sophisticated one
including pollution sensor, solar sensor and dozen of other electronic gizmos. Then i've
found that one of the fresh air vents was getting hot air from under the hood (a seal
was broken), which prevented the automatics from keepint the temp constant.

I drive now E39 with automatic aircon and it does not have this problem. I recall
fiddling with fan or drivers side temp settings maybe once every other day and
the weather here is not being easy on us.

I run it now mostly without compressor because temperatures are yet rare to
exceed 24..25c (76F) but in two weeks i will probably have to run it in "full a/c" mode
because temperatures will raise. Fan i keep on rather conservative setting
(three or four display "dashes"), center vent temperature wheel set to either
neutral or two blue dots at most, all vents open and directed towards me but
not very directly, drivers side is 19...19.5c and passenger 20 (66.68F).

During the night temperature sometimes falls as low as 6..7c (43F) but this does
not make me play with A/C settings.

Perhaps it is worth noting, that right now i usually wear quite light, comfy clothing and most of the time i have thin windbreaker jacket on while driving. Not having it i would probably keep the temperature half or one centigrade higher.
 

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I personally HATE the auto setting for the fan speed and what vents to direct air but I think this is largely subjective.

For starters and I wish I could remember the details in the thread, but do not ever put the center dial at the maximum 3 dot setting. For some reason (sorry for lack of details...I just do not recall), it messes up the A/C or heating control. At the most, keep it to 2 dots but best is one dot either way. If you don't believe me, at least try this and see what you think.

Otherwise, I tend to leave the mid-body vents off and leave the foot and window vents on and I adjust my own fan-speed as needed. On a hot day enterting an oven-like car, I just hit max and dial things down from there.
 

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Ågent99 said:
For starters and I wish I could remember the details in the thread, but do not ever put the center dial at the maximum 3 dot setting. For some reason (sorry for lack of details...I just do not recall), it messes up the A/C or heating control. At the most, keep it to 2 dots but best is one dot either way. If you don't believe me, at least try this and see what you think.
I wasn't going to reply to this thread til I saw 99's post. I mostly use the center vent control to raise/lower the temp in the car. I go to three reds if I am cold, three blues if I am hot. I'll punch the snowflake button if I need the AC, but we haven't gotten to that part of late Spring/Summer yet where it's always necessary. 99 - by "messes up" do you mean "damages"? As in permanently? Or just that by using the center control it doesn't allow the climate control to function as it should while the center vents are set with three blue/red dots? Please clarify if you can. Thanks!
 

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Ågent99 said:
For starters and I wish I could remember the details in the thread, but do not ever put the center dial at the maximum 3 dot setting. For some reason (sorry for lack of details...I just do not recall), it messes up the A/C or heating control. At the most, keep it to 2 dots but best is one dot either way. If you don't believe me, at least try this and see what you think.
The three-dot blue setting does not cause any irrepairable harm to the car, but does create a situation where the car will periodically spew hot moist air into the cabin in a big surge that will be very noticeable.

The reason for this is that the car needs to vent some warm air periodically and typically mixes it with the cold air so it is fairly consistent. At three-dots, however, the car will hold it in until it explodes. The auto version of a burp.

Jim Cash has a more educated explanation but I couldn't find it just now.

Bill
 

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BillP said:
The three-dot blue setting does not cause any irrepairable harm to the car, but does create a situation where the car will periodically spew hot moist air into the cabin in a big surge that will be very noticeable.

The reason for this is that the car needs to vent some warm air periodically and typically mixes it with the cold air so it is fairly consistent. At three-dots, however, the car will hold it in until it explodes. The auto version of a burp.

Jim Cash has a more educated explanation but I couldn't find it just now.

Bill
Thanks, Bill. That is the "more info" that I couldn't remember! Those of you from Roadfly (or former flea'ers), might remember the BMW-God Jim Cash. He had a very nice explanation many years ago...all I can recall from it was "no 3 dots!" :)
 

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Interesting discussion re the blue dots. I leave mine on 3 blue dots all the time for at least 9 months out the year (it gets very hot here in south Texas -- I really should move to Calif). I've never noticed a surge of hot air, but maybe I'll change it to one or two blue dots and see if I notice any difference. In the winter (all 3 weeks of it), I set it to the middle or one or two red dots. Also, I leave it set to "auto" 90% of the time.
 

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kc5 said:
Interesting discussion re the blue dots. I leave mine on 3 blue dots all the time for at least 9 months out the year (it gets very hot here in south Texas -- I really should move to Calif). I've never noticed a surge of hot air, but maybe I'll change it to one or two blue dots and see if I notice any difference. In the winter (all 3 weeks of it), I set it to the middle or one or two red dots. Also, I leave it set to "auto" 90% of the time.
I am about to drive my car and will look but I suspect I am a 3 dotter:eek: Of course I never use my heat, mostly use the "auto" setting at 69 a little lower on real hot days. I have never felt the burp and my wife always thinks the car is too cold.
 

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Ågent99 said:
I personally HATE the auto setting for the fan speed
I'm confused.

Is this the intended operation (particularly of the auto setting)?
1. The "Driver & Passenger Temperature Selection" buttons set the temperature to aim for (by side) by mixing hot/cold air differentially
2. The "AC Compressor" switch turns the A/C on (at the preset fan speed) & off
3. The "MAX AC" option turns the fan on at maximum fan speed (for only the A/C but not the heater?) but not off
4. The "Air Volume Control" rocker turns the fan on and off from the bottom of the range, and otherwise sets the current (& default?) fan speed
5. Each "Defrost/Face/Footwell Vent" button directs the air upward, sideways, or down respectively
6. What does the AUTO (Automatic Program) button actually override with respect to 1 thru 4?


Are there any other control buttons to consider here?
 

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shaftdrive said:
I'm confused.

Is this the intended operation (particularly of the auto setting)?
1. The red & blue triangles set the temperature to aim for (by side) by mixing hot/cold air differentially
2. The snowflake turns the A/C on (at the preset fan speed) & off
3. The max snowflake turns the fan on at maximum fan speed (for only the A/C but not the heater?) but not off
4. The plus-fan-minus bar turns the fan on and off from the bottom of the range, and otherwise sets the current (& default?) fan speed
5. The up/side/down buttons direct the air upward, sideways, or down
6. What does the auto button actually override with respect to 1 thru 4?


Are there any other control buttons to consider here?
I believe auto affects #4 and #5, it changes the fan speed and where the air goes. The one thing it does NOT do that I wish it did was affect #2, turning the AC on. I would love for auto to, for example, turn on the AC when the interior is over 80F.

Bill
 

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OK, I'll share, too :) I never feel cold; I run the AC through most of the winter months (I'm in SoCal, so the winter is very mild).
  • 3 Dots
  • Both left and right are set to 72
  • manually adjust fan
  • No Auto mode
  • "Torso" vents - all open
My understanding is that three dots are OK as long as your not using Auto mode. If cabin temp drops below the pre-set level, and the thumbwheel is at 3 dots, the HVAC first cools the air, then warms it back (or something like that). I too have never felt the warm "burp". No sweaty sock odor emanating from the vents, either. Thank God.

-Mark
 

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Discussion Starter · #14 · (Edited)
markseven said:
OK, I'll share, too, 3 Dots, 72 Left & Right, manually adjust fan, No Auto mode, "Torso" vents - all open
Very interesting. I think I'll try your setup. My BMW owners manual is in the car so I'm writing this from memory. That manual recommends 72 degrees on both sides and AUTO and that's about it (as long as all the vents are open). IIRC, BMW then says the AUTO initially controls both #5 and #4 but if you have AUTO on and then you hit #4 then AUTO only controls #5 and not #4 (pretty fancy, huh).

There's a recirculate button that is not circled in the picture. It's the one below #2. That recirculate function is also on the steering wheel only it's marked with a different symbol. Even though the symbols are different, I think the two recirculate buttons do the same thing. They open or close entry of outside air.

Underneath the #3 & #4 in the photo are grilles covering the left & right temperature sensors, I think. If there are two of them, they seem to me to be so close, just inches away from each other, as to not really be capable of discerning between left and right. I am not sure if there are other sensors scattered about the interior. Of course, there is the outside temperature sensor which plays a role but its effect is not adjustable by the driver so it is of little concern in these recommendations (I guess you could unplug it if you wanted to).

I think BMW recommends the automatic setting.
... Set the center vent to 1 or 2 blue dots but not 3
... Set both left and right temperature to 72 F
... Make sure the main vents are all open
... Press the snowflake button to start the air conditioner
... Press the AUTO button for automatic fan speed & vent direction control

If we then need a cooler cabin, I think BMW recommends.
... Press the maximum air conditioning switch (#3 button)
... This should increase both the fan speed & lower the temperature by adjusting vent hot/cold mixtures
... When the desired cool cabin temperature is reached
... Press the AUTO button to resume automatic control of both air and vent location

I'll also try your manual suggestion which I think is this.
... Set the center vent to 3 blue dots
... Set both left and right temperature to 72 F (#1 buttons)
... Set the air to blow straight out & not up or down (#5 buttons)
... Make sure the "Torso" vents are all open
... Manually adjust the fan speed as desired (#4 button)
 

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For the sake of clarity, I'm using three BLUE dots. BTW, I've never used the heater in my car :)

My car doesn't have the Max AC button, nor does it have any HVAC controls on the steering wheel... hmm.... are those part of the premium package?

-Mark
 

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Well Ill chime in on this. I live in Phoenix Az. and it was over 100 today. Sunday it will be 113, So I run mine with all 3 dots in blue and both temp. settings at the lowest 60. I use it like this 24/7 here in AZ. I dont like the auto and if it gets a little cold I only turn the fan speed down a bit but I never mess w/ the a/c button or the dots. I do notice in city driving the air does not come in as cold or as powerful when making turns ...any ideas..
 

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jerrybsal said:
I do notice in city driving the air does not come in as cold or as powerful when making turns ...any ideas..
It's "draft free" ventilation, meaning that when the vents are positioned as BMW recommends, you shouldn't feel the air on you at all. The only time I feel the air directly is when making turns.

-Mark
 

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When just I am in the car:

2-3 blue dots
usually 60deg on both sides :eek: .. well, until the ambient car temp is cooled down a bit.
auto
far right vent off
rear vents off
no a/c unless it is absolutely needed, then never off again until I stop and exit the car. I hate the extra humid air that comes out after you turn off the a/c.
 

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markseven said:
My car doesn't have the Max AC button, nor does it have any HVAC controls on the steering wheel... hmm.... are those part of the premium package?
Is this the premium package HVAC control button you are referring to (see photo)?
It is below the steering-wheel-mounted cruise-control buttons on the lower-right quadrant.
I never used it myself but it looks like it could be an air recirculation button.
 

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From this photo, you can see that the recirculation button on the AC/Heater control panel has a similar, but different circular arrow look to it.

By the way, I just noticed that small "LED" in the bottom-right corner of the passenger-side temperature sensor vent grid.

I see from the Bentleys that it is a photo transistor which feeds the temperature control system somehow.

How does that photo transistor affect things?
 

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